Lehrbuch; Arbeitsbuch; Course book; Textbook; Workbook; Übungsbuch; Introductions (to linguistics) ; Evaluation criterion (information retrieval) ; LDV; Linguistic data processing ; Data base ; Sampling; Language corpus; Sprachkorpus; Datensammlung; Data collection; Textkorpus (method.) ; Text corpus (method.) ; Corpus linguistics ; Frequency (statistics)